If a pressure greater than atmospheric pressure is applied to a solution, its water potential:
3. Remains same
4. Becomes zero
Water movement in plants is:
1. Down a potential gradient in apoplast and up the potential gradient in symplast
2. Down a potential gradient in symplast and up the potential gradient in apoplast
3. Up the potential gradient in both apoplast and symplast
4. Down the potential gradient in both apoplast and symplast
What per cent of water reaching them is used by leaves in photosynthesis?
1. Less than 1%
2. About 5 %
3. About 5 % in warm conditions and about 10 % in cold conditions
4. About 50 %
Attraction of water molecules to polar surfaces [such as the surface of tracheary elements] is called as:
What are the control points where a plant adjusts the quantity and types of solutes that reach the xylem?
1. Suberin deposited casparian strips
2. Transport proteins of endodermal cell
3. Sclerenchyma around the pericycle
4. The root hairs themselves
Consider the following two statements:
I. The direction of movement in the phloem is bi-directional.
II. The source-sink relationship in plants is variable.
1. Both I and II are correct and II explains I
2. Both I and II are correct but II does not explain I
3. I is correct but II is incorrect
4. Both I and II are incorrect
During translocation of sugars in plants from source to sink:
1. The loading of sugar at source is by active transport and unloading at the sink by passive transport.
2. The loading of sugar at source is by passive transport and unloading at the sink by active transport.
3. Both loading at the source and unloading at the sink are by active transport.
4. Both loading at the source and unloading at the sink are by passive transport.
It is a common observation that CAM plants are not tall. The reason most likely is:
1. They would be unable to move water and minerals to the top of the plant during the day.
2. They would be unable to supply sufficient sucrose for active transport of minerals into the roots during the day or night
3. Transpiration occurs only at night, and this would cause a highly negative in the roots of a tall plant during the day.
4. Since the stomata are closed in the leaves, the Casparian strip is closed in the endodermis strip is closed in the endodermis of the root.
Water logging or over-watering a plant is dangerous and may kill the plant. Why is this so?
1. Water does not have all the necessary minerals a plant needs to grow.
2. Water neutralizes the pH of the soil.
3. The roots are deprived of oxygen.
4. Water lowers the water potential of the roots.
1. Water is lost from the cytoplasm but not from the vacuole
2. Water is first lost from the cytoplasm and then from the vacuole
3. Water is first lost from the vacuole and then from the cytoplasm
4. Water is lost from the vacuole but not from the cytoplasm